How to Troubleshoot the Navigation System

General Operation

Refer to the Honda Navigation Systerm Owner's manual for the navigation system operating procedures.

Anti-theft Feature

The navigation system has a coded theft protection circuit. Be sure to get customer's five-digit security code number before;

  • disconnecting the battery
  • disconnecting the navigation unit connector
  • removing the No. 8 (15A) fuse from the passenger's under-dash fuse/relay box

After service, reconnect power to the navigation unit, and turn the ignition switch ON (II). Enter the five-digit security code.

When replacing the navigation unit, be sure to give the customer the new anti-theft security code.

Symptom Diagnosis

Certain circumstances and system limitations will result in occasional vehicle positioning errors. Some customers may think this indicates a problem with the navigation system when, in fact, the system is normal. Keep the following items in mind when interviewing customers about navigation system symptoms.

Self-Inertial Navigation Limitations

The limitations of the self-inertial portion of the navigation system (the yaw rate sensor and the vehicle speed signal) can cause some discripancies between the vehicle's actual position and the indicated vehicle position (GPS vehicle position). However, if GPS signals cannot be received, you must tune the vehicle position manually.

The following circumstances may cause vehicle positioning errors:

  • Moving the vehicle with the engine stopped, such as by ferry or tow truck, or if the vehicle is spun on a turn table
  • Tire slippage, changes in tire rolling diameters, and some driving situations may cause discrepancies in travel distances. Examples of this include:
    • Continuous tire slippage on a slippery surface
    • Driving with snow chains mounted
    • Abnormal tire pressure
    • Incorrect tire size
    • Frequent lane changes across a wide highway
    • Continuous driving on a straight or gently curving highway
  • Tolerances in the system and map inaccuracies sometimes limit how precisely the vehicle position is indicated. Examples of this include:
    • Driving on roads not shown on the map (map matching is not possible)
    • Driving on a road that winds in one derection, such as a loop bridge, an interchange, or a spiral parking garage
    • Driving on a road with a series of sharp hair-pin turns
    • Driving on one of two close parallel roads
    • After making many 90 degree turns

Global Positioning System (GPS) Limitations

The GPS cannot detect the vehicle's position during the following instances:

  • For the first five to ten minutes after reconnecting the battery
  • When the satellite signals are blocked by tall building, mountains, tunnels, large trees, or large trucks
  • When the GPS antenna is blocked by something on the dashboard
  • When there is no satellite signal output (Signal output is sometimes stopped for satellite servicing)

  • When the satellite signals are blocked by the operation of some electronic after market accessories.

The accuracy of GPS is reduced during these instances:

  • When only two satellite signals can be received (Three satellite signals are required for accurate positioning)
  • When the satellite control centers are experiencing problems

LCD Display Unit Limitations

  • In cold temperatures, the display may stay dark for the first two or three minutes until it warms up.
  • When the display is too hot because of direct summer sunlight, it will remain dark until the temperature drops.
  • When the humidity is high and the interior temperature is low, the display may appear cloudy. The display will clear up after some use.

Symptom Duplication

  • When the symptom can be duplicated, follow the self-diagnostic procedures (picture diagnosis mode) and the appropriate troubleshooting procedures.
  • When the symptom does not reappear or only reappears intermittently, ask the customer about the conditions when the symptom occured.
    • Try to establish if outside interference may have been the cause.
    • Try to duplicate the symptom under the same conditions the customer was experiencing.
    • Vibration, temperature extremes, and moisture (dew, humidity) are factors that are difficult to duplicate.

Service Precautions

  • Before disconnecting the battery, make sure you have the anti-theft codes for the radio and the navigation system, and write down the frequencies for the radio's preset buttons.
  • After servicing, park the vehicle in an area where the GPS satellite signals will be unobstructed, and check the satellite mark on the display.
  • When the battery is disconnected, the clock is reset to ‘‘0:00''. The clock will reset to the correct time after the system receives the GPS satellite signals.
  • After reconnecting the battery, you have to wait to get the initial signal from the satellite. It will take about ten minutes.